Ring-Planet

Planetary gear consisting of drive, ring and planetary gears with adjustable gear ratio and friction losses.

blockType: Engee1DMechanical.Transmission.Gears.Planetary.Auxiliary.RingPlanet

Path in the library:

/Physical Modeling/1D Mechanical/Gears/Planetary Subcomponents/Ring-Planet

Description

Block Ring-Planet It consists of a driving gear, an annular gear, and a set of planetary gears. The planetary gears engage with the driving gear and rotate with it. The planetary and ring gears rotate at a fixed gear ratio, which you specify. Ring-planetary gears and solar-planetary gears are the main elements of a planetary gearbox.

ring planet 1

The thermal model

You can simulate the effects of heat flow and temperature changes by turning on an additional heat port. To use the thermal port, set the parameter Friction model meaning Temperature-dependent efficiency.

The equations

Ideal gears and transmission ratios

Block Ring-Planet imposes one kinematic and one geometric constraint on three connected axes:

The gear ratio for engagement of the ring and planetary gears is:

where — the number of teeth on each gear. From the point of view of this relation, the key kinematic constraint is:

Three degrees of freedom are reduced to two independent pairs of gears: .

Gear ratio There should be a planetary transmission .

The transmission of torque is carried out as follows:

Ideally, when there is no loss in torque transmission, .

Imperfect limitations and losses in gears

In an imperfect case . For more information, see the article Modeling of mechanical gears with losses.

Assumptions and limitations

The inertia of the gears is negligible.
Gears are treated as solids.

Variables

Use the parameter group Initial Targets to set the priority and initial target values for the block parameter variables before modeling. For more information, see Configuring physical blocks using target values.

Ports

Conserving

# With — driving gear
rotational mechanics

Details

A non-directional port connected to the drive gear.

Program usage name

carrier_flange

# P — planetary gear
rotational mechanics

Details

A non-directional port connected to a planetary gear.

Program usage name

planet_flange

# R — ring gear
rotational mechanics

Details

A non-directional port connected to an annular gear.

Program usage name

ring_flange

# H — heat flow
warm

Details

A non-directional port connected to the heat flow.

The thermal port allows you to simulate the heat flow between the unit and the connected network.

Dependencies

To use this port, set the parameter Friction model meaning Temperature-dependent efficiency.

Program usage name

thermal_port

Parameters

Main

# Ring (R) to planet (P) teeth ratio (NR/NP) — gear ratio from ring gear to planetary gear

Details

Constant gear ratio, , the revolutions of the annular gear to the number of revolutions of the planetary gear. It is determined by the number of teeth of the ring gear divided by the number of teeth of the planetary gear. The gear ratio must be >1.

Default value	`2`
Program usage name	`ratio`
Evaluatable	Yes

Meshing Losses

# Friction model — the friction model
No meshing losses - Suitable for HIL simulation | Constant efficiency | Temperature-dependent efficiency

Details

The model of friction in transmission. Set as:

No meshing losses - Suitable for HIL simulation – gear engagement is considered ideal.
Constant efficiency – the transmission of torque between the gear pairs is reduced by a constant amount of efficiency, , such that .
Temperature-dependent efficiency – the transmission of torque between pairs of gears is determined by the interpolation table of temperature correspondence and the efficiency of torque transmission.

Values	`No meshing losses - Suitable for HIL simulation` \| `Constant efficiency` \| `Temperature-dependent efficiency`
Default value	`No meshing losses - Suitable for HIL simulation`
Program usage name	`friction_model`
Evaluatable	No

# Ordinary efficiency — Torque transmission efficiency

Details

Torque transmission efficiency, , for gearing the outer and inner pairs of planetary gears. This value must be in the range (0,1].

Dependencies

To use this parameter, set Friction model on Constant efficiency.

Default value	`0.98`
Program usage name	`efficiency_const`
Evaluatable	Yes

Details

A vector of temperature values used to construct an interpolation table of temperature and torque transmission efficiency. The elements of the vector should increase monotonously.

Dependencies

To use this parameter, set for the parameter Friction model meaning Temperature-dependent efficiency.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`[280.0, 300.0, 320.0] K`
Program usage name	`temperature_vector`
Evaluatable	Yes

# Efficiency — vector of efficiency values

Details

Vector of efficiency values, , for gear engagement of ring and planetary gears.

The block uses these values to build an interpolation table of temperature and efficiency correspondence.

Each element is an efficiency related to the temperature vector of the parameter Temperature. The length of the vector must be equal to the length of the vector of the Temperature parameter. Each element of the vector must be in the range (0,1].

Dependencies

To use this parameter, set for the parameter Friction model meaning Temperature-dependent efficiency.

Default value	`[0.95, 0.9, 0.85]`
Program usage name	`efficiency_vector`
Evaluatable	Yes

# Planet-carrier power threshold — minimum threshold power value
W | uW | mW | kW | MW | GW | V*A | HP_DIN

Details

The power threshold value, when exceeded, the full efficiency value is applied. If the value is lower than the specified value, the efficiency value is smoothed using a hyperbolic tangent function.

If set for the parameter Friction model meaning Constant efficiency The unit reduces losses to zero when no power is transmitted.
If set for the parameter Friction model meaning Temperature-dependent efficiency The unit smooths the efficiency coefficients between zero at rest and the values indicated in the interpolation tables of temperature correspondence and efficiency of torque transmission.

Dependencies

To use this parameter, set for the parameter Friction model meaning Constant efficiency or Temperature-dependent efficiency.

Units	`W` \| `uW` \| `mW` \| `kW` \| `MW` \| `GW` \| `V*A` \| `HP_DIN`
Default value	`0.001 W`
Program usage name	`power_threshold`
Evaluatable	Yes

Viscous Losses

# Planet-carrier viscous friction coefficient — coefficient of viscous friction between gears
N*m*s/rad | mN*m*s/rad | kN*m*s/rad | kgf*m*s/rad | lbf*ft*s/rad

Details

The coefficient of viscous friction for the movement of planetary and bearing gears.

Units	`Nms/rad` \| `mNms/rad` \| `kNms/rad` \| `kgfms/rad` \| `lbffts/rad`
Default value	`0.0 Nms/rad`
Program usage name	`viscous_coefficient`
Evaluatable	Yes

Thermal Port

# Thermal mass — heat capacity
J/K | kJ/K

Details

The thermal energy required to change the temperature of a component by one degree. The higher the heat capacity, the more resistant the component is to temperature changes.

Dependencies

To use this parameter, set for the parameter Friction model meaning Temperature-dependent efficiency.

Units	`J/K` \| `kJ/K`
Default value	`50.0 J/K`
Program usage name	`thermal_mass`
Evaluatable	Yes